This invention relates generally to latch devices and deals more particularly with a latch which is specially constructed to hold down hatch covers of the type found on railroad hopper cars, as well as to latch similar closure panels.
Railroad hopper cars are typically provided with a plurality of hatch covers which serve as doors to open and close the hatches through which materials are loaded into the hopper cars. Railcars commonly known as "sugar" cars have relatively large hatch covers which are in turn each equipped with a number of smaller hatches or portholes. These porthole hatches are covered by small circular hatch covers which open and close on the main hatch covers. The purpose for the porthole hatches is to permit sugar and similar materials to be loaded into the hopper car through spouts which are extended through the small porthole hatches rather than the larger hatches which remain closed. The interior of the hopper car and its contents are thus protected from contamination because dirt and other foreign materials are less likely to be blown into the small round porthole hatches than into the larger main hatches. Of course, the main hatches can be opened to load various other types of materials when contamination is not a particularly serious problem.
Because of the benefits obtained in the loading of sugar cars, the use of small porthole hatches in the larger hatch covers has become rather common. However, the need for additional hatch covers has caused problems. For example, additional latches are required to retain both the large and small hatch covers in the closed position. In the past, latches of the type commonly found on suitcases and briefcases have been used extensively for railcar hatch covers. This type of latch is unduly expensive and is not always easy to manipulate, particularly after it has been in service for an extended period of time. Also, conventional latches are lacking somewhat in reliability and tend to release accidentally when subjected to rough handling and other forces that can be expected in normal service. All of these problems are compounded when additional latches are required such as when additional hatch covers are needed for the porthole hatches of sugar cars.